Vantilating system and method for controlling the same

ABSTRACT

Ventilating system for introducing outdoor air and discharging room air, and method for controlling the same, the ventilating system including a duct for making a room and an outside of the room in communication, a ventilator connected to the duct for discharging room air to an outside of the room, and supplying outdoor air to the room through the duct, a window controller provided to each window for opening/closing the window individually, and a controller for controlling the ventilator and the window controller for ventilating the room. The method for controlling a ventilating system includes the steps of measuring conditions of room air and outdoor air, determining a ventilating method and a ventilating rate according to the measured conditions, and ventilating the room by opening/closing the window automatically, and putting a ventilator into operation according to a result of determination.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of co-pending application Ser. No.11/147,431 filed on Jun. 8, 2005, and for which priority is claimedunder 35 U.S.C. §120; and this application claims priority ofApplication No. P2005-0012316 filed in Korea on Feb. 15, 2005 under 35U.S.C. § 119; the entire contents of all are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to ventilating systems, and moreparticularly, to a ventilating system for introducing outdoor air anddischarging room air, and a method for controlling the same.

2. Discussion of the Related Art

A ventilating system is provided to a general house or an apartment forventilating rooms. Such a ventilating system is provided with a ductthat forms a moving passage of air. The ventilating system is providedwith, in general, an air supply fan and an air discharge fan, and theduct is, in general, provided with an air supply duct and an airdischarge duct. In operation, when the air supply fan is driven, outdoorair is supplied to the room through the air supply duct, and when theair discharge fan is driven, the room air is discharged to an outside ofthe room, thereby ventilating the room.

In the meantime, in case of a new building, there are much VolatileOrganic Compounds (VOC), such as formaldehyde, emitted from variousconstruction materials. It is known that such volatile organic compoundscause dermatitis, and cancer. In a case there are much volatile organiccompounds in the room, it is required to ventilate the room, quickly.

However, sizes of the air supply, and discharge ducts, and outputs ofthe air supply fan and the air discharge fan are fixed already, anamount of outdoor air supplyable in a unit time period, and an amount ofroom air dischargeable to an outside of the room in a unit time period,are limited. Therefore, in a case the room air is polluted heavily, theroom can not be ventilated, quickly. In order to solve such a problem,it is required to design the air supply, and the air discharge ductslarger, and provide larger capacity air supply fan, and air dischargefan. However, in this case bulky ventilating system and ducts impedeseasy mounting thereof.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a ventilating system,and a method for controlling the same that substantially obviates one ormore problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a ventilating system,and a method for controlling the same, which can ventilate a room whenthe room is polluted heavily.

Another object of the present invention is to provide a ventilatingsystem for introducing outdoor air and discharging room air, and amethod for controlling the same, which can ventilate a room taking acontent of volatile organic compounds of room air into account.

A further object of the present invention is to provide a ventilatingsystem, and a method for controlling the same, which can improve aventilating capability of the ventilating system without providinglarger ventilating system and ducts.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, aventilating system includes a duct for making a room and an outside ofthe room in communication, a ventilator connected to the duct fordischarging room air to an outside of the room, and supplying outdoorair to the room through the duct, a window controller provided to eachwindow for opening/closing the window individually, and a controller forcontrolling the ventilator and the window controller for ventilating theroom.

The ventilating system may further include a VOC sensor for measuring acontent of volatile organic compounds of the room air. The ventilatingsystem may further include sensors for measuring conditions of outdoorair and room air. The sensors include a room temperature sensor formeasuring a temperature of the room air, a room humidity sensor formeasuring humidity of the room air, an outdoor temperature sensor formeasuring a temperature of the outdoor air, and an outdoor humiditysensor for measuring humidity of the outdoor air.

The window controller includes a control unit for opening/closing thewindow, and a driving unit connected to the control unit for generatinga driving force.

The window controller makes the window to slide sideways to open/closethe window. In this case, the control unit includes a housing connectedto the window, the housing having a helical hole, and an elongated screwcoupled to the driving unit and placed in the helical hole for movingthe window connected to the housing as the screw is rotated by thedriving unit. The driving unit may include a driving motor coupled tothe screw with a shaft, or a gear box connected to one end of the screw,and a driving motor coupled to the gear box with a shaft.

The window controller pushes/pulls the window forward/backward toopen/close the window. In this case, the control unit includes a drivengear connected to the window, and a driving gear connected to thedriving unit, and engaged with the driven gear, for being rotated by thedriving unit to rotate the driven gear, for opening/closing the window.The driven gear is coupled to the rotating shaft of the window with ashaft, and the driving unit includes a driving motor coupled to thedriving gear with a shaft.

The controller determines a ventilating method and a ventilating ratetaking the content of volatile organic compounds of the room air, andcontrols the ventilator and the window controller, accordingly. Thecontroller closes the window when the room air is polluted lower than apreset highest reference value.

The controller determines the ventilating method and the ventilatingrate taking the outdoor temperature into account additionally when theroom air is polluted higher than a preset highest reference value, andcontrols the ventilator and the window controller, accordingly. Thecontroller closes the window, and puts the ventilator into operation,for ventilating the room, if the outdoor temperature is outside of apresent range.

The controller determines the ventilating method and the ventilatingrate taking a temperature difference between the room and outside of theroom if the outdoor temperature is within a preset range, and controlsthe ventilator and the window controller. The controller opens thewindow to ventilate the room if the temperature difference between theroom and outside of the room is within a preset range. The controllercloses the window and puts the ventilator into operation, forventilating the room, if the temperature difference between the room andthe outside of the room is outside of the preset range.

In the meantime, in another aspect of the present invention, a methodfor controlling a ventilating system includes the steps of measuringconditions of room air and outdoor air, determining a ventilating methodand a ventilating rate according to the measured conditions, andventilating the room by opening/closing at least one windowautomatically, and putting a ventilator into operation according to aresult of determination.

The step of determining a ventilating method and a ventilating ratefurther includes the step of determining a degree of pollution of theroom air being within a preset range. The degree of pollution of theroom air is dependent on a content of volatile organic compounds of theroom air.

The step of ventilating the room includes the step of closing the windowif the degree of pollution of the room air is within a preset range. Thestep of ventilating the room includes the step of closing the window andstopping the ventilator if the degree of pollution of the room air islower than a lowest reference value. The step of ventilating the roomincludes the step of closing the window and operating the ventilator ata low rate if the degree of pollution of the room air is higher than alowest reference value and lower than a highest reference value.

The step of determining a ventilating method and a ventilating ratefurther includes the step of determining the outdoor temperature ofbeing within a preset range if the degree of pollution of the room airis higher than a preset range. The step of ventilating the room includesthe step of closing the window and putting the ventilator into operationif the outdoor temperature is outside of a preset range.

The step of determining a ventilating method and a ventilating ratefurther includes the step of determining the temperature differencebetween the room and the outside of the room being within the presetrange if the outdoor temperature is within the preset range. The step ofventilating the room further includes the step of opening the window andstopping the ventilator if the temperature difference between the roomand outside of the room is within a preset range.

The step of determining a ventilating method and a ventilating ratefurther includes the step of determining outdoor relative humidity ofbeing within a preset range if the temperature difference between theroom and the outside of the room is within a preset range. The step ofventilating the room includes the step of opening the window to themaximum if the outdoor relative humidity is within a preset range. Thestep of ventilating the roof further includes the step of opening thewindow to the minimum if the outdoor relative humidity is outside of thepreset range.

The step of ventilating the room further includes the step of closingthe window and putting the ventilator into operation if the temperaturedifference between the room and the outside of the room is outside ofthe preset range.

The step of determining a ventilating method and a ventilating ratefurther includes the step of determining room relative humidity of beingwithin a preset range if the temperature difference between the room andthe outside of the room is outside of the preset range. The step ofventilating the room further includes the step of closing the window andoperating the ventilator at a maximum rate if the room relative humidityis within the preset range. The step of ventilating the room furtherincludes the step of closing the window and operating the ventilator ata minimum rate if the room relative humidity is outside of the presetrange.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings;

FIG. 1 illustrates a plan view of a ventilating system in accordancewith a preferred embodiment of the present invention provided to abuilding;

FIG. 2 illustrates a block diagram of the ventilating system in FIG. 1;

FIG. 3 illustrates a window controller of the ventilating system in FIG.1 in accordance with a first preferred embodiment of the presentinvention, schematically;

FIG. 4 illustrates a window controller of the ventilating system in FIG.1 in accordance with a second preferred embodiment of the presentinvention, schematically; and

FIG. 5 illustrates a flow chart showing the steps of a method forcontrolling a ventilating system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Referring to FIGS. 1 and 2, the ventilating system of the presentinvention includes a duct 100 making a room and an outside of the roomin communication, a ventilator 200 connected to the duct 100, fordischarging room air to an outside of the room through the duct 100, andsupplying outdoor air to the room, window controllers 300, and 400mounted to the windows W1, and W2 for opening/closing the windows W1,and W2 respectively, and a controller 500 for controlling the ventilator200 and the window controllers 300, and 400, for ventilating the room.

Referring to FIG. 1, the duct 100 includes an air supply duct 110 forsupplying outdoor air to rooms, and a discharge duct 120 for dischargingroom air to an outside of the rooms. At the end of the air supply duct110 connected to the room, there is an air supply diffuser providedthereto, and at the end of the air discharge duct 120, there is an airdischarge diffuser provided thereto. For reference, the air supplydiffusers and the air discharge diffusers are marked with circles atends of the air supply duct and the air discharge duct 120.

The ventilator is, for an example, installed at a balcony, and has anair supply fan (not shown) and an air discharge fan (not shown). The airsupply fan is in communication with the air supply duct 110, forsupplying outdoor air to the room through the air supply duct 110. Theair discharge fan is in communication with the air discharge duct 120,and discharges room air to an outside of the room through the airdischarge duct 120.

The ventilator 200 may further include a preheat exchanger (not shown).The preheat exchanger is provided to, for an example, an inside of acase to the ventilator 200, for making the outside air being supplied tothe room and the room air being discharged to an outside of the room tocross and heat exchange, indirectly. Accordingly, thermal energy of theroom air discharge to an outside of the room is recovered by the outdoorair supplied to the room through the preheat exchanger, to improve athermal efficiency of the ventilating system of the present invention,accordingly.

The ventilator 200 may further includes a filter (not shown). The filteris mounted on, for an example, the preheat exchanger, for filteringoutdoor air and room air introduced into the preheat exchanger.Therefore, the ventilating system of the present invention alwayssupplies filtered clean air only, according to which the room maintainsa comfortable state.

In the meantime, the window controllers 300, and 400 may be provided tosome or all of the windows. The window controller 300 or 400 of thepresent invention is applicable both to a window W1 for opening/closingthe window by sliding the window in a left/right direction, and a windowW2 for opening/closing the window by pushing/pulling in aforward/backward direction. Such window controllers 300, and 400 will bedescribed with reference to FIGS. 3 and 4, in more detail.

FIG. 3 illustrates a window control device of the ventilating system inFIG. 1 in accordance with a first preferred embodiment of the presentinvention, schematically.

Referring to FIG. 3, the window controller 300 can open/close a windowW1 by sliding the window W1 in a left/right directions, and includes acontrol unit 310 for opening/closing the window W1, and a driving unit320 for driving the control unit 310.

The control unit 310 includes, for an example, a housing fixedly securedto a frame of a window W1 to be closed/opened by sliding the window W1in a left/right direction, and a screw 312 connected to the driving unit320 and engaged with the housing 311. In more detail, the housing has ahelical hole in an inside surface thereof, passed through, for anexample, the housing 311. The screw 312 has one end connected to a shaftof the driving unit 320, and the other end placed in the helical hole topass through the housing 311. Therefore, when the screw 312 is rotatedby the driving unit 320, rotation of the screw 312 is converted into alinear motion of the housing 311 by the helical hole, to move the windowW1 together with the housing 311 in a left/right direction as thehousing slides in the left/right direction.

The driving unit 320 that drives the control unit 310 includes a gearbox 321 of a predetermined gear ratio, having the screw 312 coupledthereto with a shaft, and a driving motor 322 coupled to the gear box321 with a shaft. The gear box 321 has an appropriate gear ratio takinga moving speed of the window W1 into account. The control unit 310 isnot limited to this. For an example, the control unit 310 may onlyincludes a driving motor coupled to one end of the screw 312 with ashaft.

In the meantime, the window controller 300 applicable to a window W1 tobe opened/closed as the window slides in a left/right direction is notlimited to above example. As another example, the window controller 300may include a belt, a sprocket, and a motor. In more detail, thesprocket includes a driving sprocket mounted on the motor, and a drivensprocket arranged a predetermined space away from the driving sprocket.The belt connects the driving sprocket to the driven sprocket, and thewindow W1 frame is connected to the belt. Accordingly, if the motor isdriven, the belt rotates together with the driving sprocket, and,according to this, the window W1 connected to the belt moves. As anotherexample, the window controller 300 may include a pinion rotated by amotor, and rack fixed secured to the window W1 and engaged with therack.

FIG. 4 illustrates a window controller 400 of the ventilating system inFIG. 1 in accordance with a second preferred embodiment of the presentinvention, schematically.

Referring to FIG. 4, the window controller 400 is applicable to a windowW2 which can be opened/closed by pushing/pulling the window inforward/backward, and includes a control unit 410 mounted on the windowW2, and a driving unit 420 connected to the control unit 410 forgenerating a driving force.

The control unit 410 is, for an example, includes a driven gear 411mounted on the window W2, and a driving gear 412 coupled to the drivingunit with a shaft and engaged with the driven gear. The driven gear 411is coupled to a rotating shaft of the window W2 with a shaft, foropening/closing the window W2 while rotating with the driving gear 412when the driving gear 412 is rotated by the driving unit 420. A gearratio of the driven gear 411 to the driving gear is fixed taking anopen/close speed of the window W2, and a rotating torque of the windowW2. The window controller 400, that can open/close the window, is notlimited to above. As another example, the window controller 400 mayinclude a hydraulic cylinder.

Moreover, though not shown, the window controller 300, or 400 mayfurther include a safety device (not shown) which senses a portion of ahuman body, or a foreign matter get in the window W1, or W2, and stopsoperation of the driving unit 320, or 420, for preventing the usersuffering from wound, and the window controller 300, or 400 frombreaking, effectively.

The controller 500 controls the ventilator 200 and the window controller300, and 400 according to conditions of room air and outdoor air. Forthis, the ventilating system of the present invention further includes aplurality of sensors for measuring conditions of the room air and theoutdoor air as shown in FIG. 2.

In more detail, the sensors are a VOC sensor 550 for measuring a contentof the volatile organic compounds in the room air, a room temperaturesenor 510 for measuring a room temperature, a room humidity sensor 520for measuring a relative humidity of the room, an outdoor temperaturesensor 530 for measuring an outdoor temperature, and an outdoor relativehumidity sensor 540 for measuring an outdoor relative humidity. Thesensors are electrically connected to, and makes communication with thecontroller. The “electrically connected to, and makes communicationwith” means both wire/wireless communication.

The sensors may be, for an example, in the case of the ventilator 200.In more detail, the outdoor temperature sensor 530 and the outdoorhumidity sensor 540 are mounted to a first inlet (not shown) throughwhich the ventilator 200 draws the outdoor air, the room temperaturesensor 510, the room humidity sensor 520, and the VOC sensor 550 may bemounted to a second inlet (not shown) through which the ventilator 200draws the room air. It is preferable that sensors are mounted such thatthe conditions of the room, and outdoor air are measured before theroom, and outdoor air pass through the preheat exchanger. In themeantime, if the sensors are provided to an inside of the case of theventilator 200, lengths of electric wire or communication cable can bemade shorter, which enables easy installation of the ventilating system.

Opposite to this, the sensors may be mounted to the diffusers. For anexample, the outdoor air sensor 530 and the outdoor humidity sensor 540may be mounted to the air supply diffuser, and the room temperaturesensor 510, the room humidity sensor 520, and the VOC sensor 550 may bemounted to the air discharge diffuser.

Referring to FIG. 5, after measuring conditions of room air and outdoorair with above sensors, i.e., the temperature and the humidity of theroom, and outdoor air, and the content of the volatile organic compoundsof the room air (S100), the foregoing ventilating system fixes aventilating method and a ventilating rate, or puts the ventilator 200into operation according to measured conditions, and opens/closes thewindows W1, and W2 automatically according to the fixed result. In thisinstance, the controller 500 operates the ventilator 200 and the windowcontrollers 300, and 400, selectively, or at the same time.

When the ventilator 200 is operated, the room air is discharged to anoutside of the room through the air discharge duct 120 and the preheatexchanger, and the outdoor air is supplied to the room through thepreheat exchanger and the air supply duct 110, thereby ventilating theroom forcibly by using the ventilator 200. Opposite to this, if thewindow controller 300, or 400 opens the window W1, or W2, the outdoorair is supplied to the room and the room air is discharged to an outsideof the room by natural convection, thereby ventilating the room,naturally. In this instance, by controlling degrees of opening of thewindow W1, or W2, the ventilating rate can be adjusted, i.e., if thedegrees of opening of the window W1 or W2 is great, the room can beventilated, quickly. A method for controlling a ventilating system inaccordance with the present invention will be described in more detailwith reference to FIG. 5.

The controller 500 fixes a ventilating method and a ventilating rateaccording to degrees of pollution of the room air, i.e., according to acontent of the volatile organic compounds of the room air. For this, thecontroller determines whether the content of the volatile organiccompounds of the room air is higher than a highest reference value (Kppm) with reference to the value measured at the VOC sensor 550 (S110).If the content of the volatile organic compounds of the room air islower than the highest reference value (K ppm), then, the controller 500determines whether the content of the volatile organic compounds of theroom air is higher than a lowest reference value (R ppm) (S111).

If the content of the volatile organic compounds of the room air islower than the lowest reference value (R ppm), i.e., if the degrees ofpollution of the room air is low, no ventilation is required.Accordingly, the controller 500 closes the window W1, or W2, and stopsthe ventilator, for ventilating the room no more (S112). However, if theroom air is polluted more or less, i.e., the content of the volatileorganic compounds of the room air is within a predetermined range, i.e.,higher than Rppm and lower than Kppm, it is required to ventilate theroom slowly. Accordingly, the controller 500 closes the window W1 or W2,and operates the ventilator 200 at a low rate, for ventilating the room,slowly (S113).

As a result of measurement of the degree of pollution of the room air,if the degrees of pollution of the room air is high, i.e., if thecontent of the volatile organic compounds of the room air is higher thanthe highest reference value Kppm, the controller 500 takes the outdoorair into account additionally in determining the ventilating method andthe ventilating rate. For this, controller 500 determines if the outdoorair is within a preset range, for an example, higher than 8° C. andlower than 40° C. (S120). Herein, the 8° C. suggested as a lowestreference temperature and the 40° C. suggested as a highest referencetemperature are a temperature people feel chilly, and a temperaturepeople feels very warm, respectively. The lowest and highest referencetemperatures may be varied taking environments of the regions where theventilating system is used, or preference of residence into account.

When the outdoor air temperature falls outside of a preset range, i.e.,when the outdoor air temperature condition is very bad as the outdoortemperature is lower than 8° C., or higher than 40° C., the controller500 does not open the window W1, and W2. This is because the very low orhigh temperature outdoor air can be introduced into the room quickly ifthe window W1, or W2 is opened, to deteriorate the room environment.Therefore, in this case, the controller 500 operates the ventilator 200at a low rate in a state the window W1, or W2 is closed, to ventilatethe room, slowly (S121). Then, the outdoor air having heat exchanged atthe preheat exchanger is introduced into the room, to enable ventilationof the room while preventing outdoor air of bad temperature conditionfrom being introduced into the room, effectively.

When the outdoor air is within a preset range, i.e., an outdoortemperature condition is appropriate, the controller 500 determines aventilating method and a ventilating rate taking a temperaturedifference between the room and outside of the room into account,additionally. For this, the controller 500 determines whether thetemperature difference between the room and outside of the room isbelow, for an example, 3° C. or not (S130).

If the temperature difference between the room and outside of the roomis below 3° C., the room temperature condition does not become poorsubstantially even if outdoor air is introduced into the room, directly.Therefore, the controller 500 opens the window W1 or W2 for ventilatingpolluted room, quickly. In this instance, as an adequate rate ofventilation is available through the opened windows W1 and W2, theventilator 200 is not operated. However, if required, the window W1 andW2 can be opened, and the ventilator 200 can be put into operation aswell.

If the temperature difference between the room and the outside of theroom is small, the controller 500 determines the ventilating rate,taking a relative humidity of the outdoor air introduced into the roomthrough the window W1 and W2 into account, additionally. For this, thecontroller 500 determines whether the relative humidity of the outdoorair is within a preset range, for an example, higher than 40% and lowerthan 60% (S140).

If the relative humidity of the outdoor air is within a preset range,the room environment does not change suddenly even if a large amount ofoutdoor air is introduced into the room at a time. Accordingly, in thiscase, the controller 500 opens the window W1, and W2 to the highest,and, as described before, the ventilator 200 is not put into operation(S141). However, if the relative humidity of the outdoor air is outsideof the preset range, the room environment is likely to become poor if alarge amount of the outdoor air is introduced into the room at a time.Accordingly, in this case, the controller 500 opens the window W1, andW2 to the lowest, and, as described before, the ventilator 200 is notput into operation (S142).

In the meantime, if the temperature difference between the room andoutside of the room is outside of the preset range, for an example,exceeds by 3° C., the room environment can be changed suddenly, if thewindow W1, and W2 is opened to introduce the outdoor air into the room,directly. Therefore, in this case, the controller 500 determines theventilating rate of the ventilator 200 taking the relative humidity ofthe room air into account additionally in a state the windows W1 and W2are closed. For this, the controller 500 determines whether the relativehumidity of the room air is within a preset range, for an example,higher than 40% and lower than 60% (S150).

If the relative humidity of the room air is within a preset range,implying that the room environment is comfortable in view of humidity, alarge amount of room air may be supplied. Accordingly, in this case, thecontroller 500 operated the ventilator 200 at a highest rate in a statethe windows W1, and W2 are closed, to ventilate the room, quickly(S151). However, if the relative humidity of the room air is outside ofthe preset range, implying that the room environment is not comfortableeven in view of humidity, it is preferable that the outdoor air issupplied at a lowest rate as far as possible. Therefore, in this case,the controller 500 operates the ventilator 200 at the lowest rate in astate the windows W1, and W2 are closed, to ventilate the room, slowly(S152). In the meantime, if required in the step 150, the controller 500may determine with reference to the relative humidity of the outdoor airlike the step 140 instead of the relative humidity of the room air.

As has been described, the present invention permits to ventilate a roomwith a ventilator forcibly, or with a window controller naturally bynatural convection. According to this, the room air can be ventilatedsuitable to conditions of outdoor air and room air. Moreover, when theroom is polluted heavily, the room can be ventilated, quickly.

Moreover, the ventilating system of the present invention can ventilateroom with reference to a content of volatile organic compounds of theroom air. Accordingly, harm to the resident caused by the volatileorganic compounds can be prevented in advance.

Furthermore, a ventilating capability of the ventilating system can beimproved without providing larger ventilator or duct. Accordingly, theventilator may be installed at a balcony, or the like easily, and theduct can be installed within a ceiling easily.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A ventilating system comprising: a duct which communicates a roomwith an outside of the room; a ventilator which ventilates the roomforcibly to discharge the room air to an outside of the room, and supplyoutdoor air to the room through the duct connected to the ventilator; awindow controller provided to each window, wherein the window controlleropens or closes the window to control to ventilate the room naturally; asensing device which senses pollutants in the room air, and conditionsof the outdoor air and the room air; and a controller which actuates atleast one of the ventilator and the window controller to ventilate theroom at least one of forcibly and naturally according to a result ofsensing by the sensor.
 2. The ventilating system as claimed in claim 1,wherein the sensing device comprises a VOC sensor for measuring acontent of volatile organic compounds of the room air.
 3. Theventilating system as claimed in claim 1, wherein the sensing devicecomprises: a room temperature sensor for measuring a temperature of theroom air; and a room humidity sensor for measuring humidity of the roomair,
 4. The ventilating system as claimed in claim 1, wherein thesensing device comprises: an outdoor temperature sensor for measuring atemperature of the outdoor air; and an outdoor humidity sensor formeasuring humidity of the outdoor air.
 5. The ventilating system asclaimed in claim 1, wherein the window controller makes the window toslide sideways to open/close the window.
 6. The ventilating system asclaimed in claim 1, wherein the window controller pushes/pulls thewindow forward/backward to open/close the window.
 7. A method forcontrolling a ventilating system comprising the steps of: measuringconditions of room air and outdoor air; determining a ventilating methodand a ventilating rate according to the measured conditions; andventilating the room by opening/closing at least one windowautomatically, and putting a ventilator into operation according to aresult of determination.
 8. The method as claimed in claim 7, whereinthe step of determining a ventilating method and a ventilating ratefurther includes the step of determining a degree of pollution of theroom air being within a preset range.
 9. The method as claimed in claim8, wherein the degree of pollution of the room air is dependent on acontent of volatile organic compounds of the room air.
 10. The method asclaimed in claim 8, wherein the step of ventilating the room includesthe step of closing the window if the degree of pollution of the roomair is within a preset range.
 11. The method as claimed in claim 8,wherein the step of ventilating the room includes the step of closingthe window and stopping the ventilator if the degree of pollution of theroom air is lower than a lowest reference value.
 12. The method asclaimed in claim 8, wherein the step of ventilating the room includesthe step of closing the window and operating the ventilator at a lowrate if the degree of pollution of the room air is higher than a lowestreference value and lower than a highest reference value.
 13. The methodas claimed in claim 8, wherein the step of determining a ventilatingmethod and a ventilating rate further includes the step of determiningthe outdoor temperature of being within a preset range if the degree ofpollution of the room air is higher than a preset range.
 14. The methodas claimed in claim 8, wherein the step of ventilating the room includesthe step of closing the window and putting the ventilator into operationif the outdoor temperature is outside of a preset range.
 15. The methodas claimed in claim 13, wherein the step of determining a ventilatingmethod and a ventilating rate further includes the step of determiningthe temperature difference between the room and the outside of the roombeing within the preset range if the outdoor temperature is within thepreset range.
 16. The method as claimed in claim 15, wherein the step ofventilating the room further includes the step of opening the window andstopping the ventilator if the temperature difference between the roomand outside of the room is within a preset range.
 17. The method asclaimed in claim 15, wherein the step of determining a ventilatingmethod and a ventilating rate further includes the step of determiningoutdoor relative humidity of being within a preset range if thetemperature difference between the room and the outside of the room iswithin a preset range.
 18. The method as claimed in claim 17, whereinthe step of ventilating the room includes the step of opening the windowto the maximum if the outdoor relative humidity is within a presetrange.
 19. The method as claimed in claim 15, wherein the step ofventilating the room further includes the step of opening the window tothe minimum if the outdoor relative humidity is outside of the presetrange.
 20. The method as claimed in claim 15, wherein the step ofventilating the room further includes the step of closing the window andputting the ventilator into operation if the temperature differencebetween the room and the outside of the room is outside of the presetrange.
 21. The method as claimed in claim 15, wherein the step ofdetermining a ventilating method and a ventilating rate further includesthe step of determining room relative humidity of being within a presetrange if the temperature difference between the room and the outside ofthe room is outside of the preset range.
 22. The method as claimed inclaim 21, wherein the step of ventilating the room further includes thestep of closing the window and operating the ventilator at a maximumrate if the room relative humidity is within the preset range.
 23. Themethod as claimed in claim 15, wherein the step of ventilating the roomfurther includes the step of closing the window and operating theventilator at a minimum rate if the room relative humidity is outside ofthe preset range.